The present invention relates to a biofungicide. In particular, the present invention relates to a microorganism, Bacillus licheniformis strain SB3086, which controls the growth of fungal organisms, including plant diseases caused by fungi, and a composition comprising said strain SB3086.
Diseases caused by fungal species are considered among the most widespread and damaging of plants worldwide. Presently, control of plant fungal diseases is largely dependent upon the application of certain chemicals. Although some of these chemicals are known to have negative environmental and human health problems, nevertheless such chemical agents continue to be in wide use due to their strong activity against important fungal diseases, and availability of environmentally safer and effective alternatives.
Generally, biological control of diseases commonly infecting plants in the root zone (rhizosphere) and the leaf zone (phylloplane) are preferred over more traditional synthetic chemical control methodologies. Such biocontrol agents usually cause little or no injury to the plant host or the environment, and some may even favor normal plant development. However, most such biocontrol organisms are typically very limited either in the scope of their effectiveness against fungal diseases, or in their ability to survive under practical field conditions and during treatment applications.
Attempts have been made to control plant fungal diseases by using certain microorganisms. For example, U.S. Pat. No. 5,589,381 (Neyra and Sadasivan, 1996) describes a Bacillus licheniformis strain PR1-36a with some ability to inhibit certain plant pathogens. However, efforts to apply certain live biological control organisms have been greatly limited by the narrow range of their effectiveness against plant pathogens, or by the inherent instability of these organisms. Many strains often. succumb within weeks to standard storage conditions, or within hours to typical field conditions involving relatively high temperatures, desiccation after spraying, and harmful effects of ultraviolet sunlight (UV) on the actively growing organism. Attempts to culture such organisms on-site at the location where the biocontrol strain would be applied have found some utility. However, serious difficulties with culture contamination, and the necessity for evening application to avoid temperature and UV effects often prove difficult, labor intensive, expensive, and impractical. Therefore, an environmentally safe and effective biological control method of inhibiting damage to plants caused by fungal diseases has heretofore not been achieved and it remains a long felt need in the agricultural industry over currently used hazardous chemicals.
It is, therefore, an object of the present invention to provide an environmentally favorable and effective biological agent for the control of a broad range of plant fungal diseases and other fungal organisms.
It is a further object of the present invention to provide a formulation and a biological method for controlling plant fungal diseases utilizing a unique strain of Bacillus licheniformis SB3086. The use of this strain SB3086 provides a practical, naturally occurring alternative to standard xenobiotic chemical agents, thereby providing an environmentally safer means to achieve fungal disease control or elimination in plants.
It is an additional object of the present invention to provide a composition containing said SB3086 strain in a form suitable for application to plants. Such a composition may contain such common components known to one of ordinary skill in the art, as non-toxic surfactants, non-toxic amounts of plant nutrients, preservatives and the like, and may be in the form of active vegetative spores, liquid, flowable powder, granules, spray dried material or with another carrier material.
Another object of the present invention is to provide a method for controlling plant fungal diseases utilizing the biofungicide of the present invention. The biofungicide may be applied to the shoot, the root, the seeds, vegetative propagules or as a soil or plant treatment in any suitable form, such as a liquid, a spray, a powder, root dip, a granule, a dust and the like containing active vegetative cells